FLOOD10133

• County: Statewide
• Community: State of North Carolina
• Basin: Statewide
• Title: Two Months of Flooding in Eastern North Carolina, September-October 1999: Hydrologic, Water-Quality, and Geologic Effects of Hurricanes Dennis, Floyd and Irene
• Date: 1/1/2000
• Prepared By: USGS
• Floodplain - Doc Type: Flood Documentation Report

livestock, and over-
whelmed municipal
waste-treatment plants.
The risk to public
health from flood-
waters contaminated
by pathogenic bacteria
Of viruses \vas a major
concern. Twenty-four
samples were collected
for the analysis of
E. coli and C. perFin-
gen.\' bacteria. These
samples were ana-
lyzed, using membrane
filtration methods, at
the USGS laboratory at
Columbus, Ohio, E. Flooded farm
coli and C. pe/fringen" are non-
pathogenic organisms, but their

Flooded houses in Goldsboro, N.C.

presence indicates con-
tamination from human
or animal wastes. The
USEPA single-sample
ambient water-quality
criterion for E. coli bacte-
ria density in recreational
waters is 235 colonies
per 100 milliliters (co Is/
100 mL) (USEPA,
1986b), Because C.
pe/ji-ingens forms an
environmentally resistant

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~

spore, the bacteria has been proposed
as an indicator for the presence of
other environ-
mentally resistant
microorganisms
that are patho-
genic. No water-
quality criterion
has been estab-
lished for C.
perfringens.
Densities of
E. coli ranged
from 57to 13,000
colsll 00 mL
and densities of
C. perlringens
from 5 to

...

Secondary road in Johnston County

170 cols/IOO mL
(fig. 14). The maxi-
mum E. coli density
occurred in the Neuse
River at Fort Barn-
well (site 32,
fig. 14A). Densities
greater than 5,000
colsll 00 mL occurred
in the Neuse River at
Clayton (site 25), Tar
River at Louisburg
(site 8), and Cape
Fear River (site 40).
All but the Lumber
ii\ River and Contentnea
o
g Creek had E. coli
densities that
exceeded the USEPA criterion. Gen-
erally, C. perfringens is much less
abundant in natural waters than
E. coli, and measured densities of
C. perfringens were, at most sites,
two orders of magnitude less than
E. coli, Neuse River sites had some-
what greater densities of C. perFin-
gens than the Tar River sites
(fig. 14B), probably reflecting higher
point-source discharges to the Neuse
River. Maximum densities of C. per-
ji-ingens occurred in the Neuse River
at Clayton (site 22) and Neuse River
at Smithfield (site 23)-both of
which are fairly near large municipal
wastewater-treatment plant out-
falls-and Contentnea Creek
(site 31). The lowest densities of
C. pe/ji'ingen.\' occurred in the North-
east Cape Fear and Lumber Rivers,
neither of which have large munici-
pal point sources.
Samples were collected during
two or more different streamflow
conditions at sites 14, 16,21,22,27,
28,40, and 43 (table 6). As flood-
waters receded, a decrease in E. coli
density was observed for Tar River at
" Tarboro, Neuse River near Clayton
'"
S and at Smithfield, and Cape Fear
Z River. In the Neuse River near

Two Months of Flooding in Eastern North Carolina. September--octobcr 1999